The disclosure relates to an adjustable hydrostatic axial piston machine of swash plate design.
An adjustable hydrostatic axial piston machine of swash plate design has a pivot cradle, on which a swash plate is arranged, on which a multiplicity of working pistons are supported. In order to adjust a pivoting angle of the pivot cradle, an actuating apparatus is known with a cylinder/piston unit and with an actuating spring which acts counter to the latter. Here, either a positive stroke of an actuating piston of the cylinder/piston unit or a positive stroke of the actuating spring can lead to pivoting of the pivot cradle out of a neutral or zero position.
DE 199 49 169 C2 discloses an adjustable hydrostatic axial piston machine of swash plate design, in which the cylinder/piston unit is arranged so as to lie opposite the actuating spring in relation to the pivot cradle. Here, a longitudinal axis of the cylinder/piston unit is set against a drive shaft of the axial piston machine. It is a disadvantage of the solution that the actuating spring has to be of comparatively long configuration, in order to pivot the pivot cradle out of the neutral position. As a result, the axial piston machine is of long construction, in particular in the axial direction. Since the actuating spring has to be compressed or prestressed for installation, both the actuating spring and the pivot cradle are difficult and complicated to install. Furthermore, it is disadvantageous that the actuating spring does not have any axial guidance, apart from at its end sections, and is loaded with transverse forces, since, during pivoting of the pivot cradle, an articulation point of the actuating spring on the pivot cradle is displaced radially or transversely with regard to an articulation point of the actuating spring, which articulation point is fixed to the housing. Since the longitudinal axis of the cylinder/piston unit is set against the drive shaft, an actuating force which is to be applied for pivoting is additionally comparatively high.
The data sheet RDE 92703-05-L/09.08 from the applicant discloses an adjustable hydrostatic axial piston machine of swash plate design which is comparable with DE 199 49 169 C2, with a modified adjustment type but with the same disadvantages.
DE 10 2006 061 145 A1 discloses an adjustable hydrostatic axial piston machine of swash plate design, in which the cylinder/piston unit is likewise arranged so as to lie opposite the actuating spring in relation to the pivot cradle. In a deviation from the prior art shown, the cylinder/piston unit is arranged parallel to the drive shaft in order to reduce the actuating force to be applied, and the actuating piston is supported via a sliding pad on an identical sliding face of the swash plate, on which the working pistons are also supported. In addition, firstly the actuating piston and the working pistons and secondly their sliding pads are of structurally identical configuration, which reduces the outlay in apparatus and manufacturing terms. However, it is still a disadvantage of the solution that the actuating spring is long, with the result that firstly the actuating spring and the pivot cradle are difficult to install and secondly the actuating spring is loaded with transverse forces during pivoting of the pivot cradle.
In contrast, the disclosure is based on the object of providing an adjustable hydrostatic axial piston machine of swash plate design which is of smaller overall construction.